Wednesday, July 30, 2014

The deep ocean

"... the only other place comparable to these marvelous nether regions, must surely be naked space itself, out far beyond atmosphere, between the stars, where sunlight has no grip upon the dust and rubbish of planetary air, where the blackness of space, the shining planets, comets, suns, and stars must really be closely akin to the world of life as it appears to the eyes of an awed human being, in the open ocean, one half mile down."

William Beebe, 1934.

As fishing and the harvesting of metals, gas and oil have expanded deeper and deeper into the ocean, colleagues are trying to draw attention to the services provided by the deep sea, the world's largest environment.

In a review of over 200 papers, an international team of researchers points out how vital the deep sea is to support our current way of life. It nurtures fish stocks, serves as a dumping ground for our waste, and is a massive reserve of oil, gas, precious metals and the rare minerals we use in modern electronics, such as cell phones and hybrid-car batteries. Further, hydrothermal vents and other deep-sea environments host life forms, from bacteria to sponges, that are a source of new antibiotics and anti-cancer chemicals. It also has a cultural value, with its strange species and untouched habitats inspiring books and films from "20,000 Leagues Under the Sea" to "Finding Nemo."

Ocean areas deeper than 200 m represent 98.5% of the volume of our planet that is hospitable to animals. They have received less attention than other environments because they are vast, dark and remote, and much of them are inaccessible to humans. But the deep ocean has important global functions. In their paper the researchers e.g. show that deep-sea marine life plays a crucial role in absorbing carbon dioxide from the atmosphere, as well as methane that occasionally leaks from under the seafloor. In doing so, the deep ocean has actually limited much of the effects of climate change.

These type of processes occur over a vast area and at a very slow rate. Manganese nodules, deep-sea sources of nickel, copper, cobalt and rare earth minerals, take centuries or longer to form and are not renewable. Similarly, slow-growing and long-lived species of fish and coral in the deep sea are more susceptible to over-fishing.

According to the authors it is about time to discuss deep-sea stewardship before exploitation is too much farther underway. The deep sea is already facing impacts from climate change and, as resources are depleted elsewhere, is being increasingly exploited by humans for food, energy and metals like gold and silver. By highlighting the importance of the deep sea and identifying the traits that differentiate this environment from others, the researchers hope to provide the tools for effective and sustainable management of this habitat.